During chlorine disinfection of drinking water, halogenated disinfection byproducts (DBPs) are generated from the reactions among natural organic matter, inorganic ions and chlorine. Recently, aromatic halogenated DBPs have raised increasing public concern, due to their significantly higher toxicity than aliphatic halogenated DBPs. In this study, with ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry (UPLC/ESI-tqMS), three new aromatic halogenated DBPs were confirmed in a 12-h simulated chlorinated drinking water sample, including tetrabromo-4-hydroxy-acetophenone, dibromo-4-hydroxy-acetophenone, and 3-bromo-5-formylsalicylic acid. Besides, it was found that when DBPs were separated using the UPLC with gradient eluent, their rete...[ Read more ]

During chlorine disinfection of drinking water, halogenated disinfection byproducts (DBPs) are generated from the reactions among natural organic matter, inorganic ions and chlorine. Recently, aromatic halogenated DBPs have raised increasing public concern, due to their significantly higher toxicity than aliphatic halogenated DBPs. In this study, with ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry (UPLC/ESI-tqMS), three new aromatic halogenated DBPs were confirmed in a 12-h simulated chlorinated drinking water sample, including tetrabromo-4-hydroxy-acetophenone, dibromo-4-hydroxy-acetophenone, and 3-bromo-5-formylsalicylic acid. Besides, it was found that when DBPs were separated using the UPLC with gradient eluent, their retention times (RTs) had a direct relation with their structures: aliphatic DBPs were eluted before aromatic ones, and DBPs with longer RTs tended to be more toxic. Moreover, a new method was developed to separate aliphatic and aromatic DBPs using UPLC based on their RT ranges (with RT 2.5 min as the dividing line). With this method, the DBPs in simulated chlorinated drinking water samples with different contact times from 0.5 to 72 h were separated into aliphatic and aromatic fractions. The total organic halogen (TOX) and developmental toxicity were examined for both fractions of each water sample. The results showed that in the first 12 h, the TOX of the aromatic fraction was higher than that of the aliphatic fraction, and after 12 h, the TOX of the aliphatic fraction became higher than that in the aromatic fraction. However, for the samples with short contact times (< 2 h), the toxicity of the aromatic fraction (with higher TOX concentration) was lower than that of the aliphatic fraction. To explain this, UPLC/ESI-tqMS analyses were conducted for each sample, and several groups of intermediate DBPs with RTs on the boundary of aliphatic and aromatic DBPs were discovered. These intermediate DBPs might form at short contact times and present high toxicity, and thus need to be further studied.